Bibcode
Villanueva, V.; Ibar, E.; Hughes, T. M.; Lara-López, M. A.; Dunne, L.; Eales, S.; Ivison, R. J.; Aravena, M.; Baes, M.; Bourne, N.; Cassata, P.; Cooray, A.; Dannerbauer, H.; Davies, L. J. M.; Driver, S. P.; Dye, S.; Furlanetto, C.; Herrera-Camus, R.; Maddox, S. J.; Michałowski, M. J.; Molina, J.; Riechers, D.; Sansom, A. E.; Smith, M. W. L.; Rodighiero, G.; Valiante, E.; van der Werf, P.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 470, Issue 4, p.3775-3805
Advertised on:
10
2017
Citations
31
Refereed citations
29
Description
We present an extragalactic survey using observations from the Atacama
Large Millimeter/submillimeter Array (ALMA) to characterize galaxy
populations up to z = 0.35: the Valparaíso ALMA Line Emission
Survey (VALES). We use ALMA Band-3 CO(1-0) observations to study the
molecular gas content in a sample of 67 dusty normal star-forming
galaxies selected from the Herschel Astrophysical Terahertz Large Area
Survey (H-ATLAS). We have spectrally detected 49 galaxies at
>5σ significance and 12 others are seen at low significance in
stacked spectra. CO luminosities are in the range of (0.03-1.31) ×
1010 K km s-1 pc2, equivalent to log
({M}_{gas}/M_{⊙}) =8.9 - 10.9 assuming an αCO = 4.6
(K km s-1 pc2)-1, which perfectly
complements the parameter space previously explored with local and
high-z normal galaxies. We compute the optical to CO size ratio for 21
galaxies resolved by ALMA at ˜3.5 arcsec resolution (6.5 kpc),
finding that the molecular gas is on average ˜ 0.6 times more
compact than the stellar component. We obtain a global Schmidt-Kennicutt
relation, given by log [Σ _SFR/(M_{⊙} yr^{-1} kpc^{-2})]
=(1.26 ± 0.02) × log [Σ _{{M}_{H2}}/(M_{⊙}
pc^{-2})] - (3.6 ± 0.2). We find a significant fraction of
galaxies lying at `intermediate efficiencies' between a long-standing
mode of star formation activity and a starburst, specially at
LIR = 1011-12 L⊙. Combining our
observations with data taken from the literature, we propose that star
formation efficiencies can be parametrized by log [{SFR/{M}_{H_2}}] =
0.19 × {(log {L_{IR}} - 11.45)}-8.26- 0.41 × arctan [-4.84
(log {{L}_{IR}}-11.45) ]. Within the redshift range we explore (z <
0.35), we identify a rapid increase of the gas content as a function of
redshift.
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